7 
5 fod ee 
7 ewe yee, 
UJ 
ENTOMOSTRACA OF MINNESOTA. 187 
a, Eye near the end of the head. ye ey AMASHICE pS, 202: 
b. Eye not near the end of the head. 
* Abdominal processes free. . . . . . . #£Kalbergensis, 203 
** Abdominal processes united. Nas ae hee eo s Cucullata,.203 
[Not in the key: dubia, 196; pennata and curvirostris, 194; thorata,197;. 
hermani, 198; similis, 204; bolivarl, 205; carinata, 205; lumholtzii, 206. }, 
Daphnia scheefferi Baird. 
PLATE LI, Fies. 1-5. 
Daphnia pennata — Mueller. 
Daphnia pulec—Straus, Koch (fide P. E. Mueller). 
Daphnia magna—Lilljeborg, Leydig, ete. 
The largest species of the genus, is of an elongated oval and ven- 
tricose form. The head is short and evenly rounded, The spine is. 
entirely absent in old females and of only moderate length in the 
young. The antennules of the male are long and have a very long. 
flagellum. The post-abdomen is narrowed suddenly below the anus 
so that the spines consist of two sets; the terminal claws are spiny at 
the base. The species may be recognized at once by the concavity of 
the dorsal] margin of the post-abdomen. The plate will make any de- 
tailed description superfluous. A common species in Europe, but not 
yet found in America, 
The sole distinction between this species and D. magna Straus is. 
found in the fact that the intestinal cceca are very long and recurved 
in D. schefferi and short and thickened at the free extremity in D. 
magna. We fail to discover sufficient reason for separating them. 
Daphnia psittacea Baird. 
Baird 750; Schoedler 758; Fric’72!; Kurz’74; Hellich’77; Herrick ’84; Elymann’873. 
Daday ’88. 
Head short, rounded in front, beak very short. A depression sepa- 
rates the head from the oval, ventricose body. Spine long directed 
dorsad. Eye distant from the margin of the head. Post-abdomen 
long, narrowed toward the end, somewhat sinuous in the caudal 
margin. Anal teeth about ten. Claw bipectinate, rather long. 
Length 1.8 to 1.9 mm. 
This species is at once recognized by the head, which is very short 
and evenly curved, or nearly so, from the heart to the beak. The 
shell is high, oval, with a rather short spine. The fornices are wide 
and angled behind. The antennules are longer than in most species; 
the post-abdomen is very large, but narrows toward the end and has 
comparatively few anal teeth, which are of unequal size. This is one 
of the largest of the genus. Not yet found in America. 
